溴甲酚绿光度法测定水样中的阳离子表面活性剂

Spectrophotometric Method for Determination of Cationic Surfactants in Water with Bromocresol Green

在pH值为6．17左右的NaH2PO4-Na2HPO4溶液中，澳甲酚绿与阳离子表面活性剂：十六烷基三甲基澳化铵（CTMAB）、澳化十六烷基吡啶（CPB）形成离子缔合物，溶液蓝色减褪。可用于测定水体中的阳离子表面活性剂，最大褪色波长为614nm。表面活性剂浓度在0—2．4×10^-5mol／L（CTMAB）、0—2．1×10^-5mol／L（CPB）范围内符合比耳定律；摩尔吸光系数分别为9．65×10^3L·mol^-1·cm^-1（CTMAB）、7．81×10^3L·mol^-1·cm^-1（CPB）；检测限为：6．12×10^-7mol／L（CTMAB）、4．59×10^-7mol／L（CPB）。方法能用于生活用水、污水处理厂进出口水中阳离子表面活性剂的测定。实验获得了满意的结果。

In＇ the NaH2PO4-Na2 HPO4 solution, in which the pH indicator is 6.17, can form ionic compound with the bromine cresol green and cationic surfactanta： cetyltrim ethylammonium bromide ammonium （CTMAB ） or cetylpyridinium bromide （CPB ） ,the blue colors of solutions fade obviously. The cationic surfactants can be used for determining in the water body. The largest wavelength is 614nm. The Mole sucks coefficient of cetylpyridinium bromide respectively is 9.65 × 10^3 L· mol^-1 · cm^-1. The mole sucks coefficient of cetyltrim ethylammonium bromide is 7.81 × 10^3 L · mol ^-1· cm^ -1. The density of cationic surfactantswith within the range of 0 - 2.4 × 10^-5 mol/L（CTMAB） to 0 - 2.1 × 10^-5 mol/L（CPB） accords with the Bill hw. Examination limit： 6.12 × 10 ^-7 mol/L（CTMAB） ,4.59 × 10^-7 mol/L（CPB）. The method can be used in the determine of cationic suffactants of the survey of living water, sewage farm import-exit water. The experiment has obtained the satisfactory result.